The point ends of drills



(No Model.) sheets-sheet 1.

, A.. PALMER 8 P. E. 4BLAGKMORE. APPARATUS POR GRIN-DING-THE POINT ENDSOP DRILLS, &c.

No. 490,588. Patented Jan. 24.1898..

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THE'NOHRIS PETEHF co, mum-Uma.; wfsnmcmn. D. cA

(No Mode1. 4 Sheets-Sheet 2.

A. PALMER& F. E. BLACKMORE. APPARATUS PoR GPINDING THE POINT ENDS oPDRILLS, aw.

No. 490,588. Patented Jan. 24, 1893.

(No Model.) 4 Sheets-Sheet v3.

A. PALMBR&' F, E. BLACKMORE. APPARATUS FOB. GRINDINGTHE POINT B-NDS OPDRILLS., &;c.

No. 490,588. Patented Jan. 24,1893.

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(No Model.) 4 Sheets-Sheet 4.

A. PALMBR&- P. BLAGKMORB. APPARATUS POR GRINDING THE POINT ENDS 0FDRILLS, 6m.

NQ. 490,588. Patented Jan. 24, 1893.

WITNESSES i' TTED STATES PATENT OEEicE.

ALFRED PALMER AND FRANCIS ERNEST BLAOKMORE, OF READING, ENGLAND.

APPARATUS FOR GRINDING THE POINT ENDS OF DRILLS, 80C.

SPECIFICATION forming part of Letters Patent No. 490,588, dated January24, 1893.

Application tiled J une 27, 1892.

To all whom it may concern:

Be it known that we, ALFRED PALMER, biscuit-manufacturer, of the lirm ofHuntley da Palmers, residing at Reading, and FRANCIS ERNEST BLACKMORE,engineer, in the employ of the said firm, residing at 55 Queens Road,Reading, in the county of Berks, England, have invented certainImprovements in Apparatus for Grinding the Point Ends of Drillsor forLike Grinding Operations, of which the following is a specification. l

The object of this invention is to provide apparatus for grinding thepoint ends of drills or for like operations and is especially suited forefficiently grinding the point ends of twist drills so that they areground or backed off by one continuous operation without requiringadjustment for different sized drills,

A but capable of ready adjustment to grind the point ends to anyrequired angle and with any required degree of backing od, the grindingbeing effected so as to give an equal amount of clearance and length oflip at both sides. The apparatus moreover enables the drill to be groundso that it has a true central point at its end so that the drill can bestarted to work in a very small center hole and the drill during itswork continues to make its own center on which it works so as to keepthe drill true and prevent its sides bearing upon the sides of the holebeing bored, which is a defect in the use of drills as hitherto groundwithout a true central point.

An apparatus constructed according to this invention consists of a frameor bed plate which may be mounted in connection with an emery wheel orlike grinding device as usual. The drill to be ground is held in a.holder capable of revolving in a bearing on an arm centered to the bedplate at the end nearest to the emery wheel and at a point such that thepoint of the drill being ground is in the axial line of the center onwhich the said arm turns. The said arm is adjustable to the angle towhich the point end of the drill is to be ground. This angle may bedetermined by a gage bar which is arranged to be brought into its gagingposition so that its gaging edge is truly parallel with the transverseline of the periphery of the emery wheel and cuts at a right angle theaforesaid axial line. The

Serial No. 438,349. (No model.)

holder carrying the drill is rotated and as it rotates the arm carryingthe bearing of the said holder is vibrated or oscillated upon its centerto alter the angle at which the point end of the drill is presented tothe emery wheel so as to give on each side of the point end thedeviation from .a cone corresponding to the amount 'of backing oli. Togive the proper cutting edge at the part of the point end of the drillwhich is between the grooves in the drill the drill is Withdrawn fromthe emery wheel or grinding device when each groove comes opposite thesaid wheel or device.

In order that our invention and the manner in which it may be carriedinto practical effect may be well understood we will describe withreference to the accompanying drawings machines constructed inaccordance with our invention.

Figure l is a plan and Fig. 2 an elevation of one arrangement. Figs. 3and 4 are corresponding views of a modified arrangement; and Figs. 5 and6 are respectivelya sectional elevation and a plan of a furthermodification in the arrangement. Fig. 7 shows a detail common to all thearrangements shown which are in principle the same and we have markedthe parts which correspond in the several arrangements with the sameletters of reference in all the figures; Fig. 8 shows a top and a sideview of the point end of the drill.

Referring to Figs. l and 2, A is the bedplate and B is the first motionshaft or stud carried in a bearing upon a standard C having a foot cwhich is provided with a projecttion engaging in the groove ot in thebed plate A and fixed in a position (according to the angle of the pointend to be ground) by the screw and nut c2. The groove c, is an arcstruck from the center a2.

b is a handle secured to a pinion B2 mounted loosely on the shaft orstud B but the pinion may be provided with a pulley for operating it bypower.

D is the movable arm centered to the bed plate A at a2, the point of thedrill being operated upon being situated in the same line as the axialline of the center a2. The said arm D has in it a bearing D2 in whichrotates the drill holderE in which the drill is secured by a chuck eorin any other convenient way. A spring' F connected at one end to thepin cs and at the other end to the pin d, respectively on the foot c andthe arm D draws the Said arm D toward the foot c. The pinion B2 mountedon the first motion shaft or stud B engages with a toothed cam wheel E2on the end of the drill holder E which cam Wheel is so shaped that asthe eccentric or projecting portions thereof come into gear with thepinion B2 the drill holder carrier D is moved away from the foot c andthe angle at which the drill is presented to the grinding' wheel isaltered twice in each revolution of the drill holder and consequentlythe drill point is ground to the amount of backing off to be given tothe said point end at each side of the drill during each revolutionthereof, the arm D carrying the drill holder turning upon its center Ca2when the revolution of the cam wheel causes the said arm to be movedaway from the foot o. By using cams of different throws the degree ofbacking olf can be varied as desired.

The point of the drill being operated upon being as aforesaid situatedin a line with the axial line of the center a2 has a true pointirnpartedto it. In order to make the sharp edges at o: Fig. 8, of the drill it isnecessary to withdraw the drill from the emery wheel when the gaps orchannels of the drill between each of the sides being ground comeopposite the said Wheel. To effect this the drill holder is movedendwise in the direction of its axis at such time which may be effectedby a face cam e2 on a collar on the holder bearing on a correspondingface cam d2 on the bearing D2 of the said holder. The spring g betweenthe bearing D2 and the collar e3 011 the holder presses the cam face e2against the cam face cl2. There are two cams on the faces e2 (Z2corresponding to the two gaps or channels in the drill being ground asshown in Fig. 7.

The gearing or device for giving the movement described may be arrangedin other ways, for instance the operating handle hand wheel or pulley bywhich rotation is given to the tool holder may be xed on the axis of thetool holder and wheel E2, as shown in dotted lines in Figs. l and 2, andthen the wheels E2 and B2can be without teeth the rotation of the camwheel E2 against the roller B2 given the vibratory or oscillatorymovement to the arm D as aforesaid.

Figs. 3 and 4 show an arrangement wherein both gearing, pinion B12 andwheel E12 are true circles, the pinion being mounted on an adjustableand tixable pin or being adjustable and fixable 011 a pin or stud B111by the nut and screw as shown, the said pin having a squared partengaging in a slot b12in the pinion B12 to adjust the degree of throwgiven to the drill holder by altering the eccentricity of the pinionB12, or the axis of the toothed wheel on the holder may be capable ofmoving and of being adjusted in aslot. The pinion B12 and wheel E12 arekept in gear by the spring F arranged as hereinbefore described.

Figs. 5 and 6 show an arrangement wherein the driving pinion B22 and itsshaft or stud B20 are carried in a prolongation of the bearing D2, thevibration of the arm D upon its center a2 being obtained by means of adisk E3 having in it a groove in which is adjustable the crank pin 112connected by the rod 7L to a standard H, the connection being made so asto allow the rod 7L to swivel in either direction and to meet anytwisting movement there may be in the rod h it can be formed in twoparts connected by screwing the one into the other at 712. Vhen thepinion B22 is rotated it rotates the drill holder as in the otherarrangements and the disk B2 being constrained by the movement rod 7Lsecured to the fixed standard H causes the arm D to vibrate on itscenter a2 twice during each rotation of the drill holder the pinion B22being half the diameter of the Wheel E22. By adjusting the pin b2 in thegroove in the disk B2 the amount of backing off can be varied. To bringthe point of the drill into the correct position in its holder beforebeing fixed so that it is in the same line as the axial line of thecenter a2 a gaging bar I is provided which is shown by the full linesout of its gaging position. Its gaging position is shown in dottedlines, its gaging edge in that position cutting at a right angle theaforesaid axial line. J indicates the position of the emery wheel whenthe drill is being ground.

It will be evident that the machine may be made to grind drills havingother number than two ribs and grooves, the gearing and cams beingarranged to give a number of vibrations to the arm D in accordance withthe number of win gs or ribs and grooves in the drill to be ground andthe cams d2 c2 being in number and position such as to withdraw thedrill as each groove comes opposite the grinder.

The apparatus may be used for grinding twist drills, points or drillpoints generally or for such other grinding operations as it is or maybe applicable to.

We claim as our invention:-

1. In an apparatus for grinding the points of drills and the like, adrill carrier capable of oscillating or vibrating on a center the eX-treme point of the drill being gaged so as to be situated in the sameaxial line as that of the center on which the said carrier oscillates orvibrates in combination with means for rotating the drill and meanswhereby as the drill rotates the angle of the carrier is altered bybeing turned upon the said center to give the required backing off ateach wing or rib of the drill on each revolution thereof substantiallyas hereinbore described.

2. In an apparatus for grinding the points of drills or the like, acarrier for the drill and means for rotating it and means whereby as thedrill revolves the angle of the carrier is altered to give the requiredbacking oif at IOO each wing or rib of the drill at each revolutionthereof and means for removing the drill from the grinder as each groovein` the drill comes opposite to it, substantially as and for the purposehereinbefore described.

3. In an apparatus for grinding the points of drills and the like, thecombination of a bed plate, an arm centered on the bed-plate, a rotatingdrill holder carried by the said arm, and a groove in the bed plate thesaid groove being an arc having its center in axial line with the centerof oscillation of the arm, with a standard adjustable in the said grooveand connections between the standard and the said arm to oscillate thearm as the drill holder rotates, all substantially as and for thepurposes set forth.

4. In an apparatus for grinding the points of drills, the combination ofa bed plate having an arm centered thereon and a groove being an arehaving its center in axial line With the center of oscillation o f thesaid arm, a rotating drill holder carriedby the arm, two cam surfaces,one on the arm and one on the drill holder, adapted to act upon eachother, with a standard adjustable in the said groove, and connectionsbetween the standard and the drill holder and arm to rotate the drillholder and oscillate the arm, all substantially as and for the purposesset forth'. n

In testimony whereof We have signed our names to this specification inthe presence of two subscribing witnesses.

ALFRED PALMER. FRANCIS ERNEST BLAOKMORE. Witnesses:

ALBT. DAVIS,

47 Lineol/Ws Inn Fields, London.

WM. JOHN WEEKS,

9 Birch/n Lane, London.

